The Optimus was one of three low-priced Android phones Sprint introduced Wednesday, joining other mobile operators launching phones with Google's popular mobile operating system at bargain prices. Sprint also unveiled the Samsung Transform for $149.99 after a $100 mail-in rebate, with a two-year contract, and the Sanyo Zio for $99.99, also after a $100 rebate and with a two-year contract. Both will go on sale Oct. 10.

The Optimus S has a 3.2-inch touchscreen and a 3.2-megapixel camera, and it comes with the Mobile Hotspot feature for connecting as many as five Wi-Fi devices to the Internet via its 3G connection. Sprint will put the Optimus S on sale Oct. 31 for $49.99 after a $100 rebate, with a two-year contract.

Android phones have been falling in price even as they proliferate and grab more of the handset market. On Tuesday, prepaid carrier Cricket announced the Ascend, an Android 2.1 phone made by Huawei Technologies that Cricket will sell for $149.99 without a contract.

The three phones Sprint introduced on Wednesday will come with Sprint ID, a new built-in system that lets consumers pick a themed interface for their phone as soon as they take it out of the box. These "ID packs" make selected applications and content available right on the home screen of the phone. Companies including ESPN, Walt Disney and eBay have created ID Packs.

Sprint ID is intended to help consumers sort through the many applications available in the Android Market and make the content they are most interested in appear conveniently at hand, Sprint CEO Dan Hesse said at an event where the platform was introduced at the CTIA Enterprise & Applications conference in San Francisco. Sprint will also help businesses put together key work applications and information in ID Packs for their employees' phones.

Having phones emblazoned with third-party identities is familiar territory for Sprint, which once sold wholesale access to its network for numerous MVNOs (mobile virtual network operators), including Disney and ESPN. Sprint ID is a way for such companies to brand a phone without the investments and commitment involved in running an MVNO, Hesse said.

However, Sprint ID reflects some of the same flawed thinking that caused most MVNOs to fail, according to NPD Group analyst Eddie Hold, who attended the event. Consumers do want help sifting through all the options on their smartphones, but they don't want a set of choices organized strictly around one brand, he said. Helping small businesses build their own ID Packs also is a good idea, but it's not likely to save companies very much work, he believes.

Carriers are rolling out inexpensive Android phones now largely for marketing rather than technology reasons, according to analyst Jack Gold of J. Gold Associates. As is typical with a new technology, carriers and vendors start it out as a premium product for early adopters and then move it down market, he said.

The danger with low-end Android phones is that they may fragment the market, NPD's Hold said.

"I think they're almost pushing them too low," Hold said. Consumers with inexpensive, low-end devices won't get the same experience or be able to run all the apps that are made for the top-end Android phones, so they may become confused. "You're going to end up with a very complicated Android portfolio," he said. Apple has largely beaten that problem by offering only the iPhone, Hold added.